Undefined array key 0 in RW::parseError() when results is an empty array

[petaak]

RW::parseError() crashes with Undefined array key 0 when the API returns a successful response with an empty results array.

This happens because parseError() is called from RO::parseResponse() for every response that contains a success key (line 1264 of RO.php), regardless of whether the operation actually failed. Some API endpoints (e.g., automaticke-parovani) return a response like:

{
   "winstrom": {
      "@version": "1.0",
      "success": "true",
      "stats": {
         "created": "0",
         "updated": "0",
         "deleted": "0",
         "skipped": "0",
         "failed": "0"
      },
      "results": []
   }
}

In parseError(), the condition on line 170 of RW.php checks array_key_exists(0, $responseDecoded['results']). When $responseDecoded['results'] is empty, this returns false, and the code falls into the else branch (line 183) which immediately tries to access $responseDecoded['results'][0]['result'] - the very key that was just confirmed to not exist.